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The addition of supplementary fat to pig diets above current dietary recommendations has generally been viewed in a negative manner because it is considered that the surplus energy will be deposited into adipose tissue, and may therefore be detrimental to carcass value. The current study sought to investigate the effects of adding supplementary fat, in place of starch, to increase the energy density of male and female pig diets on growth performance and carcass quality. A total of 288 Large White × Landrace male and female pigs (boars and gilts) were randomly allocated to pens of 12 pigs each. The effects of (i) sex (gilts v. boars), (ii) added dietary fat level (as tallow; 0 v. 40 and 80 g/kg) and (iii) within added dietary fat level (40 v. 80 g fat/kg), were tested for a 5-week period (Period 1) (n = 4). These diets were formulated to contain 13·5, 14·3 and 15·2 MJ digestible energy/kg for 0, 40 and 80 g added fat/kg, respectively; the calculated standardized ileal digestible lysine content was kept constant at 8·8 g/kg of diet. Thereafter the experiment was designed to test for the same effects over a second 5-week period (Period 2), during which pigs from the initial three treatments were offered the diets with 0 and 40 g added fat/kg. Treatment effects were also assessed over the whole 10 weeks of the study. There was a positive linear effect of dietary fat supplementation in Period 1 on average daily weight gain, whereas dietary fat level in Period 1 had no effect on performance in Period 2, overall, or on carcass weight and P2 backfat thickness (i.e. thickness of fat at 65 mm down the left side from the midline, at the level of the head of the last rib) at 10 weeks. In contrast, supplementation of the diet with 40 g fat/kg during Period 2, regardless of the diet offered in Period 1, increased ADG in the second period and over the entire experiment. There were minimal effects of supplementary fat on feed intake in the entire experiment; however feed conversion

Two experiments were conducted to determine the responses of entire male and female pigs of the Australian Pig Improvement Co. genotype to dietary lysine. In Experiment 1, a total of 350 [Large White (Landrace Duroc)] entire male and female pigs weighing 22.3 0.16 kg (mean s.e.m.) were used in a 2 by 5 factorial design with the main treatments being sex (entire males and females) and five levels of standardised ileal digestible (SID) lysine to digestible energy ratio (0.6, 0.7, 0.8, 0.9 and 1.0 g SID lysine/MJ DE). In Experiment 2, a total of 420 [Large White (Landrace Duroc)] entire male and female pigs weighing 49.6 0.34 kg (mean s.e.m.) were used in a 2 by 5 factorial design with the main treatments being sex (entire males and females) and five levels of SID lysine to MJ DE ratio (0.4, 0.5, 0.6, 0.7 and 0.8 g). From 20 to 50 kg liveweight (LW), entire males had a similar average daily gain (ADG), lower feed intake (FI, P 0.001) and better feed to gain ratio (F:G, P 0.001) compared with females. From 50 to 100 kg LW, entire males had a higher ADG (P 0.001), similar FI and improved F:G ratio (P 0.001) compared with females. Data were subjected to the quadratic response model to determine optimum SID lysine requirement for maximum ADG and minimum F:G for the weight ranges 20-35, 35-50, 50-65, 65-80, and 80 to 95 kg LW. For male pigs, maximum ADG was achieved at SID lysine levels of 1.00, 0.87, 0.72, 0.67 and 0.63 g/MJ DE, respectively. Minimum F:G was achieved at SID lysine levels of 1.00, 0.87, 0.80, 0.69 and 0.63 g/MJ DE for the respective weight ranges. For female pigs, maximum ADG was achieved at SID lysine levels of 0.90, 0.84, 0.67, 0.63 and 0.58 g/MJ DE. Minimum F:G for females was achieved at SID lysine levels of 0.86, 0.85, 0.64, 0.66 and 0.40 g/MJ DE for the respective weight ranges. The results suggest that this Australian genotype requires greater dietary SID lysine in the growing and finishing phase than the levels currently used by the Australian indus

Current iron (Fe) levels in fresh pork are below requirements to claim for a source of Fe (Anonymous, 2013). Dietary studies to increase muscle Fe in pork have generally failed, although an increase in muscle redness, associated with increased haem Fe, was observed (Apple et.al 2007). Under normal feeding conditions about 10% of dietary Fe is absorbed, however this value increases markedly under Fe deficiency (West and Oates 2008). This study tested the hypothesis that feeding lower levels of dietary Fe (depletion) followed by feeding higher levels of dietary Fe (repletion) to pigs will increase muscle Fe levels.

The objective of this study was to evaluate whether altering the timing of the secondary anti-gonadotropin-releasing factor (GnRF) immunization closer to slaughter in male finishing pigs would reduce the increase in P2 fat depth (6.5 cm from the midline over the last rib), while still limiting the incidence of boar taint. Entire male pigs are immunized against GnRF to reduce the concentration of testicular steroids that in turn limits the incidence of boar taint. Additionally, testicle measurements and color measurements were taken to examine whether they could be used to differentiate nonimmunized entire males from immunized male pigs. A total of 175 Large White x Landrace entire male pigs aged 16 wk (59 kg of BW) were used in a completely randomized design with 5 treatment groups based on the time that pigs received the secondary immunization before slaughter. Pigs were housed in groups of 7 and randomly allocated to 1 of 5 treatments with 5 replicates per treatment. The treatment groups were as follows: no secondary immunization before slaughter, and the secondary immunization given at 2, 3, 4, or 6 wk before slaughter. The P2 fat depth levels were reduced (P = 0.054) with the secondary immunization closer to slaughter (11.7, 11.3, 12.8, 12.6, and 13.7 mm for no secondary immunization, secondary immunization at 2, 3, 4, and 6 wk before slaughter, respectively). Androstenone concentration did not exceed the generally accepted industry sensory threshold of 1.0 mu g/g of fat, and both androstenone concentration in the adipose tissue and testosterone concentrations in the blood were suppressed (P < 0.001) in all immunized pigs regardless of timing of the secondary immunization compared with pigs that did not receive the secondary immunization. Skatole concentration of all pigs in the experiment did not exceed the generally accepted industry sensory threshold of 0.2 mu g/g. Testes weight was reduced (P < 0.001) with increased time between slaughter and the secondary i

Euphausiids are commonly found in the stomachs of bowhead whales Balaena mysticetus hunted near Barrow, Alaska; however, no evidence exists of a self-sustaining population in this region. To explain euphausiid presence near Barrow, their transport from the northern Bering Sea was investigated through particle tracking experiments using velocity fields from an ocean general circulation model in 4 contrasted circulation scenarios (1997, 1998, 2002 and 2003). Euphausiids were released during their spawning season (April−June) in the bottom and surface layers in the northern Bering Sea, their endemic region, and tracked through the Chukchi-Beaufort Sea. Results show that both Anadyr Gulf and Shpanberg Strait are potential regions of origin for euphausiids. Topographically steered bottom particles have 4 to 5 times higher probability of reaching Barrow than surface particles (ca. 95% versus 20% of particles). As euphausiids are often found near the bottom on the northern Bering shelf, this suggests a very high probability of euphausiids reaching Barrow, making this location a privileged area for whale feeding. The main pathways to Barrow across the Chukchi Sea shelf are Central Valley (CV) and Herald Valley (HV). The transit to Barrow takes 4 to 20 mo. Arrivals at Barrow have 2 peaks at ca. 200 d (fall, CV particles) and 395 d after release (spring, mixed CV and HV) on average, because of the seasonal cycle of the Chukchi Sea currents. Elevated euphausiid abundance in the fall at Barrow is favored by a high Bering Strait northward transport and by southerly winds, driving organisms through CV rather than through the HV pathway.

The present study was designed to determine the interrelationships between sex, weaning age, and weaning weight on subsequent growth performance. Ninety-six Large White × Landrace pigs were used in a 2 × 2 × 2 factorial experiment with the respective factors being: age at weaning (14 or 28 days), weight at weaning (heavy or light), and sex (boar or gilt). Eighty pigs were offered a high quality pelleted weaner diet ad libitum while the remaining 16 pigs (2 pigs from each treatment group) were removed from the sow and fasted for 24 h before being euthanased for determination of gut histology and enzymology. The remaining pigs were weaned into individual pens and given an ad libitum diet containing 15.5 MJ DE/kg and 0.95 g available lysine/MJ DE. On Day 6 and 13 after weaning, 2 pigs from each group at each time had their feed removed and, 24 h later, were euthanased. From 3 weeks post-weaning, the remaining pigs were group-penned with contemporary pigs and fed commercial rations until slaughter at 23 weeks of age. In the first week after weaning, the heavy pigs and those weaned at 28 days ate more feed and grew faster, and gilts ate more and grew faster than boars over the same time. Pigs that were heavier at weaning were also heavier at every subsequent age. At slaughter, heavy boars weighed more than heavy gilts (110.5 v. 103.7 kg, P = 0.027), whereas this was not the case for light boars and gilts (94.1 v. 94.4 kg, P = 0.96). Whereas there were no effects of sex or weight at weaning on P2 backfat depth, pigs weaned at 14 days had more backfat at 23 weeks than pigs weaned at 28 days (13.1 v. 10.9 mm, P = 0.009). In conclusion, these data clearly indicate that the greatest determinants of immediate post-weaning performance under the present conditions were the age and weight of the pigs at weaning. However, the key determinant of lifetime growth rate appeared to be weight of pigs at weaning or, by inference, birth. Although age at weaning had no effect on lifetime g

The present study was designed to determine the interrelationships between sex, weaning age, and weaning weight on aspects of physiological and gastrointestinal development in pigs. Forty-eight Large White x Landrace pigs were used in a factorial arrangement with the respective factors being: age at weaning (14 or 28 days), weight at weaning (heavy or light), sex (boar or gilt), and time after weaning (1, 7, and 14 days). At weaning, 48 pigs were removed from the sow; 16 pigs were then fasted for 24 h before euthanasia for determination of organ weights, gut histology, and enzymology, and 32 pigs were offered a high quality pelleted weaner diet ad libitum for subsequent assessment of organ weights, histology, and enzymology at 7 and 14 days after weaning. On Day 6 and 13 after weaning, 2 pigs from each group had their feed removed, and 24 h later were euthanased and similar measurements were taken. In general, the data highlighted the overall gastrointestinal underdevelopment of pigs weaned at 2 weeks of age and of pigs weaned light-for-age at either 2 or 4 weeks. Heavier body organs, gastrointestinal organs, and accessory digestive organs observed after weaning, except for the spleen, presumably reflected the increase in substrates available for cellular growth as feed intake increased after weaning, and the development of organs required to process this feed. Interestingly, the relative weights (% of liveweight) of the stomach and small intestine and, to a lesser extent, the caecum and colon, were greater in the light, 14-day-old weaned pigs, but these differences diminished with increasing time after weaning. Consistent effects due to age, weight, and sex were not observed for villous height and crypt depth, or for the specific activities of the brush-border and pancreatic enzymes measured. However, increases (P < 0.001) in the activities of maltase (P < 0.001), glucoamylase (P < 0.001), and sucrase (P = 0.020) (all expressed per gram of mucosa), and that of tryp

Digestive capacity of early-weaned pigs may be insufficient to fully digest many ingredients currently used in weaner diets. Ihe aim of this experiment was to determine whether an exogenous enzyme preparation with broad carbohydrase activity could benefit pigs that developmentally might be immature at weaning, especially with regard to gastrointestinal development. Eighty Large White x Landrace pigs were used in a 2 × 2 × 2 × 2 factorial experiment with the factors being: weaning age (14 or 24 days), weaning weight (heavy or light), sex (boar or gilt), and dietary Biofeed Plus CT (0 or 500 μg/g), which contained fungal xylanases, pentosanases, and β-glucanases. Pigs were housed individually and given a wheat-based (550 g/kg) diet containing 15.0 MJ DE and 15.9 g lysine/kg on an ad libitum basis for 21 days. The diet also contained 50 g/kg of soybean meal and 50 g/kg of lupin (Lupinus angustifolius) kernels. The liveweights of heavy (H) pigs weaned at 24 or 14 days and light pigs (L) weaned at 24 or 14 days were 7.9 and 5.3 and 5.2 and 3.9 kg, respectively. Pigs weaned at 14 days grew slower (157 v. 345 g/day) than those weaned at 24 days, although there was a suggestion of an interaction between age and weight at weaning (P = 0.081). Thus, H and L pigs weaned at 14 days grew at 148 and 166 g/day, whereas H and L pigs weaned at 24 days grew at 374 and 315 g/day, respectively. Although there was no main effect of enzymes on daily gain (248 v. 254 g/day, P = 0.80), feed intake (278 v. 284 g/day, P = 0.79), or feed conversion ratio (1.19 v. 1.25, P = 0.35), there were interactions with weaning age on daily gain (P = 0.050) and feed intake (P = 0.060). Pigs weaned at 14 days grew slower (176 v. 138 g/day) and ate less (206 v. 174 g/day), whereas pigs weaned at 24 days grew faster (321 v. 369 g/day) and ate more (351 v. 394 g/day), when supplemented with enzymes. During the third week after weaning there were interactions between dietary enzymes and sex (P = 0.060) and di

Seventy 14-day-old male pigs that were either heavy (6.0 kg) or light (3.6 kg) for age were weaned into individual pens and fed 1 of 7 diets containing 9.2-21.0 g lysine/kg feed in a study designed to determine the effect of dietary lysine and weight on lysine requirements of pigs. Five pigs from each weight group were used to determine initial body composition. When pigs reached 10 kg they were slaughtered and empty body composition was analysed to determine protein tissue accretion rates. Protein deposition rate was not affected by weight at weaning but increased with dietary lysine content before reaching a plateau. The relationship between protein deposition (PD, g/day) and dietary lysine (L, g/kg) was described by 3 models. The rectilinear model, which had a linear ascending phase (PD = 4.84 + 1.948L, R2 = 0.935, P = 0.002) and a horizontal component representing maximum protein deposition rate of 32.3 g/day, revealed that maximum protein deposition occurred at 14.1 g lysine/kg. The quadratic function (PD = - 2.74 + 3.74L - 0.099L2, R2 = 0.916, P = 0.003) provided an estimate of the lysine requirement of 14.9 g lysine/kg occurring at a point where PD reached 95% of the maximum protein deposition rate (32.5 g/day). Use of an asymptotic model (PD = 32.60 - 186 x 0.727L, R2 = 0.919, P = 0.003) provided an estimate of 14.9 g lysine/kg occurring at a point where PD reached 95% of the maximum protein deposition rate (32.6 g/day). These data indicate that early weaned pigs should be fed a highly digestible diet containing 14-15 g lysine/kg to maximise protein deposition.

Pigs are commonly wean~d at 23-27 days of age. By weaning earlier and providing pigs with high quality diets, it may be possible to increase growth performance up to slaughter. However, digestive capacity of early weaned pigs may be insufficient to fully digest many ingredients currently used in weaner diets. The aim of this experiment was to determine whether an exogenous enzyme preparation with broad carbohydrase activity could benefit pigs that were possibly developmentally immature at weaning.

While pigs are commonly weaned at 23-27 days of age, sow milk production peaks at 10-14 days of lactation after which it limits growth. By weaning earlier and providing pigs with a suitable diet, it may be possible to increase growth of the young pig. However, it is possible that the digestive function of early-weaned pigs may be immature and incapable of digesting many feedstuffs. The present study was designed to examine some of the factors that might influence small intestinal function in the weaned pig.

Pigs are commonly weaned at 23-27 days of age. However, sow milk production peaks at 10-14 days of lactation after which it is only sufficient for pigs to attain about 50% of their growth potential (Dunshea et al., 1995). By weaning earlier and providing pigs with a suitable diet, it may be possible to capitalize on their potential for rapid growth. The present study was designed to determine the interrelationships between sex, weaning age and weaning weight on subsequent growth performance.

Many pig producers are moving towards early weaning in an effort to minimise disease transfer from sow to piglet. However, it is possible that the digestive function of early-weaned pigs may be immature and incapable of digesting many feedstuffs. The present study was designed to examine some of the factors that might influence pancreatic enzymic function in the weaned pig.

This experiment was designed to investigate the interactions between weaning weight and dietary lysine in pigs weaned at 14 days.

The present study was conducted to determine the interrelationships between age, sex and weight at weaning, on subsequent growth performance of pigs.

In pig production, optimization of the conversion of animal feeding-stuffs into body components, especially lean meat, requires knowledge of the response relationships between nutrient intake and animal performance. In this study, the separate effects of protein and energy intake on rate and composition of body gain have been determined, in pigs with a high genetic capacity for lean tissue gain, from 20 to 45 kg. In addition, the response in body gain to energy intake has been investigated from 20 to 45 kg and from 45 to 85 kg, and the effects of body weight and previous nutrition on this response were examined. The relationship between protein intake and protein accretion was described well with a linear-plateau model, reflecting a protein and an energy dependent phase in protein deposition. The amino acid pattern of body protein was influenced by protein and energy intake. The optimal lysinelenergy ratio was not significantly affected by the level of feed intake. Protein and lipid accretion responded linearly to energy intake, both from 20 to 45 kg and from 45 to 85 kg. The increase in protein gain per unit increase in energy intake, decreased with increasing body weight. The ratio between lipid and protein deposition, and consequently body lipid content, responded curvilinearly to energy intake and increased with increasing body weight. The percentage of lean tissue decreased curvilinearly with increasing energy intake. Pigs which were restricted in energy intake from 20 to 45 kg, gained faster from 45 to 85 kg. However, this gain was largely explained by an increase in digestive tract contents and in organ gain. The percentage lean tissue at 85 kg was higher in these previously restricted pigs, but this was the result of their higher lean percentage at 45 kg, and not of a compensatory gain from 45 to 85 kg. Consequences of these results for defining an optimal feeding strategy have been discussed.